The iPhone's appeal may be settling down - at least in the US - and it's almost entirely due to the rise of Android, according to a survey conducted by market watcher ChangeWave.

In September, it asked 4000 consumers about their smartphone purchase plans. Of those who intend to buy such a gadget in the next three months, 38 per cent said they'd pick the iPhone while almost as many - 37 per cent - said they'd opt for an Android device.

The last time ChangeWave asked the question, in June 2010, 50 per cent said they'd go for the iPhone while only 30 per cent favoured an Android handset.

Patterns of Demand - the platforms consumers say they'll buy into in the next three months
Source: ChangeWave

These two platforms dominate purchase intentions. The latest survey puts the proportion of potential BlackBerry buyers at six per cent - up a single percentage point over June's figure - while Windows Mobile demand fell by the same amount, to one percentage point.

Palm's WebOS didn't trouble the scorer.

It's worth considering seasonal factors when comparing Android and iPhone. Back in June, when iPhone demand was high, Apple had just launched the iPhone 4 so you'd expect the buzz to be higher than it might usually be.

Now, with the antennagate controversy all but forgotten, the iPhone demand level seen by ChangeWave is more realistic. And that shows that the two platforms are, at the moment, equally appealing to punters.

The rise and rise of Android - percentage of buyers intending to choose the Google OS
Source: ChangeWave

But with more vendors behind Android than support iOS - almost all versus just one - the Google platform will become more diverse, appearing in high-end devices, low-end kit and all points between, and that is inevitably going to make it appeal to a broader array of buyers than the iPhone can.

An interesting side note is ChangeWave's question about how satisfied their devices are consumers. For each platform, the percentage of uses who said they were very satisfied with their smartphones came to: 74 per cent (iPhone), 65 per cent (Android), 32 per cent (WebOS), 31 per cent (BlackBerry) and 24 per cent (Windows Mobile).

Percentage of a platform's users who said they were 'very satisfied' with their smartphone
Source: ChangeWave